The overall goal of the current proposal is to examine the relationship between salivary composition and the perception of astringency. Astringency is a class of oral sensations, induced by chemical stimuli, that are described as sensations of dryness and tightening of oral tissues. Astringency involves de-lubrication of the salivary coating in the oral cavity A critical step in the development of astringency is the association of tannin molecules with salivary proteins. The literature on chemical interaction of polyphenols and proteins has recently shown how binding can be assessed using turbidity measures. Animal models have also established a connection between tannins in the diet and the expression of salivary proline-rich proteins, effective binding agents for dietary tannins. Therefore, individual difference in salivary composition, astringency response and dietary intake of tannins will also be studied. Due to the fact that many astringent substances are also bitter, this approach is extended to examine individual differences in bitter taste responses. A new model is proposed for the prediction of bitterness and astringency based on a variance-component approach. This model attempts to supplement the traditional between-groups analysis (i.e., comparison of different PROP tasting groups) with a correlational approach to estimate the degree of association or common variance among predictor variables. Overall, the research will help explain individual differences in taste and chemo-tactile oral sensations through the study of an important and complex peri-receptor medium, saliva, its composition, and perceptual influences .